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The Effect of Interlayer Anion Grafting on Water Oxidation Electrocatalysis: A Comparative Study of Ni- and Co-Based Brucite-Type Layered Hydroxides,Layered Double Hydroxides and Hydroxynitrate Salts |
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| Authors: | A V Radha Sebastian Weiß Ignacio Sanjuán Michael Ertl Prof Dr Corina Andronescu Prof Dr Josef Breu |
| Institution: | 1. Department of Chemistry, University of Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany
These authors contributed equally to this work.;2. Department of Chemistry, University of Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany Bavarian Center for Battery Technology (BayBatt), University of Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany These authors contributed equally to this work.;3. Technical Technology III and Center for Nanointegration (CENIDE), University Duisburg-Essen, Carl-Benz-Str. 199, 47057 Duisburg, Germany;4. Department of Chemistry, University of Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany |
| Abstract: | The urge for carbon-neutral green energy conversion and storage technologies has invoked the resurgence of interest in applying brucite-type materials as low-cost oxygen evolution reaction (OER) electrocatalysts in basic media. Transition metal layered hydroxides belonging to the brucite-type structure family have been shown to display remarkable electrochemical activity. Recent studies on the earth-abundant Fe3+ containing mössbauerite and Fe3+ rich Co−Fe layered oxyhydroxide carbonates have suggested that grafted interlayer anions might play a key role in OER catalysis. To probe the effect of such interlayer anion grafting in brucite-like layered hydroxides, we report here a systematic study on the electrocatalytic performance of three distinct Ni and Co brucite-type layered structures, namely, (i) brucite-type M(OH)2 without any interlayer anions, (ii) LDHs with free interlayer anions, and (iii) hydroxynitrate salts with grafted interlayer anions. The electrochemical results indeed show that grafting has an evident impact on the electronic structure and the observed OER activity. Ni- and Co-hydroxynitrate salts with grafted anions display notably earlier formations of the electrocatalytically active species. Particularly Co-hydroxynitrate salts exhibit lower overpotentials at 10 mA cm−2 (η=0.34 V) and medium current densities of 100 mA cm−2 (η=0.40 V) compared to the corresponding brucite-type hydroxides and LDH materials. |
| Keywords: | electrochemistry nickel/cobalt hydroxynitrate nitrate grafting oxygen evolution reaction water splitting |